Enhancement of terahertz radiation from coherent optical phonons via impulsive interference of excitons in GaAs/AlAs multiple quantum wells

Nakayama, Masaaki; Itoh, Satoshi; Mizoguchi, K.; Saito, Shingo; Akahane, Kouichi; Yamamoto, Naokatsu; Sakai, Kiyomi

doi:10.1016/j.jlumin.2007.11.048

Cited by 4 publications

(4 citation statements)

References 11 publications

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“…In contrast, IR reflectance and Raman scattering spectroscopy revealed that the interaction energy width of optical phonons and radiation were less than 10 cm 1 in various crystals without using any cavity structure. THz-emission was obtained as a pulse train by exciting coherent LO phonons using an ultrashort pulse laser [6][7][8][9] . Mizoguchi et al 6 and Nakayama et al 7 determined that the coherent-time duration of the LO phonon in GaAs-related superlattices can be extended to tens of picoseconds (ps).…”

Section: Introductionmentioning

confidence: 99%

“…THz-emission was obtained as a pulse train by exciting coherent LO phonons using an ultrashort pulse laser [6][7][8][9] . Mizoguchi et al 6 and Nakayama et al 7 determined that the coherent-time duration of the LO phonon in GaAs-related superlattices can be extended to tens of picoseconds (ps). On the other hand, continuous-wave thermal emission in the mid-IR region was obtained via surface phonon polariton (SPhP) based on microscopic or nanoscopic structures [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] .…”

Section: Introductionmentioning

confidence: 99%

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Longitudinal optical (LO) and LO-like phonon resonant mid-infrared radiation emission and absorption by surface micro-structures on III-nitrides

Ishitani,

Lin,

Lai Lai Aye

et al. 2024

Gallium Nitride Materials and Devices XIX

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Longitudinal optical-like phonon resonant mid-infrared emission (LORE) and absorption peaks of micro-surface line and space structures of metallic material plates on GaN wafers are observed at 500 -630 K. The emission peak energy is located in a range of 670 -730 cm -1 for GaN, which is lower than the LO-phonon energy of approximately 730 cm -1 at 630 K. This feature is contrasted with that of the LO-phonon resonant emission from the AuGaAs microstructures resonating with the LO phonon. The emission mechanism is clarified using a structure of n ++ -GaN with an electron density of 110 20 cm -3 as a metallic material. These emission lines have another notable feature, i.e., the observed peak energies are independent of the polar emission angle, unlike the emissions by surface phonon polaritons showing a significant directive nature of peak energies. The present results show that each peak energy in the emission spectrum is positioned at the zero-point of the real part of the dielectric function comprising the components of the transverse optical phonon and other electric dipoles induced by the LO-like modes, excluding the target mode. This type of emission is also obtained for the structures of AlxGa1-xN films. These results suggest the feasibility of high-efficiency emission in a range of 670 -900 cm -1 when the devices are positioned in a cavity with high reflectivity of blackbody-like radiation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Longitudinal optical (LO) and LO-like phonon resonant mid-infrared radiation emission and absorption by surface micro-structures on III-nitrides

Ishitani,

Lin,

Lai Lai Aye

et al. 2024

Gallium Nitride Materials and Devices XIX

View full text Add to dashboard Cite

show abstract

“…In contrast, IR reflectance and Raman scattering spectroscopy revealed that the interaction energy width of optical phonons and radiation were less than 10 cm -1 in various crystals without the introduction of any cavity structure. A pulsed THz emission was obtained by exciting coherent LO phonons by using an ultrashort pulse laser [6][7][8][9]. Mizoguchi et al [6] and Nakayama et al [7] determined that the coherenttime duration of the LO phonon in GaAs-related superlattices can be extended to tens of picoseconds (ps).…”

Section: Introductionmentioning

confidence: 99%

“…A pulsed THz emission was obtained by exciting coherent LO phonons by using an ultrashort pulse laser [6][7][8][9]. Mizoguchi et al [6] and Nakayama et al [7] determined that the coherenttime duration of the LO phonon in GaAs-related superlattices can be extended to tens of picoseconds (ps). Furthermore, the absorption of radiation and continuous-wave thermal emission in the mid-IR region were obtained through surface phonon polariton (SPhP) based on microscopic or nanoscopic structures [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Mid-infrared thermal radiation resonating with longitudinal-optical like phonon from n⁺⁺-doped GaN–semi-insulating GaN grating structure

Lin,

Aye,

Ueno

et al. 2023

J. Phys. D: Appl. Phys.

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The mid-infrared emission mechanism of line-and-space structures of metallic plates on dielectric materials is substantiated using high conductive n-doped (n++-) GaN–semi-insulating (SI-) GaN microstripe structures on an SI-GaN epitaxial layer, which was veiled when using line-and-space structures of Au plates. The present structure exhibits a few thermal emission lines originating from electric dipoles resonating with the coherent longitudinal optical (LO) phonon-like lattice vibration, which are formed by the local depolarization electric field in the surface n++-GaN/SI-GaN/n++-GaN regions. The energies of the LO-phonon-like modes shift from the original LO-phonon energy of GaN to the lower energy region, which contrasts with the LO-phonon resonant emission from the microstructures on GaAs. These emission lines have another notable feature, i.e., the observed peak energies are independent of the polar emission angle for both s- and p-polarizations, unlike the emissions by surface phonon polaritons showing a significant directive nature of peak energies. The results show that each peak energy of the present emission lines is positioned at the zero-point of the real part of the electric permittivity comprising the components of the transverse optical phonon and other electric dipoles induced by the LO-like modes, excluding the target mode. The significant peak-energy shift of the LO-like phonons is applicable to materials with wide Reststrahlen bands, which contrasts with that of the nearly LO-phonon resonating feature of materials with narrow Reststrahlen bands, such as GaAs. The peak energy shift depending on the emission direction is observed for Au–GaN stripe structures. This property is ascribed to the imperfect Au/GaN interface with surface states through the theoretical analysis of the modified electric permittivity in the surface region, numerical simulation of the local electric field via finite-difference time-domain calculation, and experimental studies on a Ti–GaN structure and emission peaks originating from an LO-like phonon of the α-Al2O3 substrate.

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Impact of material-dependent radiation – longitudinal optical phonon interaction on thermal electric-dipole radiation from surface metal − semiconductor grating structures

Lin,

Lai Lai Aye,

Yoshikawa

et al. 2024

Infrared Physics & Technology

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Enhancement of terahertz radiation from coherent optical phonons via impulsive interference of excitons in GaAs/AlAs multiple quantum wells

Cited by 4 publications

References 11 publications

Longitudinal optical (LO) and LO-like phonon resonant mid-infrared radiation emission and absorption by surface micro-structures on III-nitrides

Longitudinal optical (LO) and LO-like phonon resonant mid-infrared radiation emission and absorption by surface micro-structures on III-nitrides

Mid-infrared thermal radiation resonating with longitudinal-optical like phonon from n⁺⁺-doped GaN–semi-insulating GaN grating structure

Impact of material-dependent radiation – longitudinal optical phonon interaction on thermal electric-dipole radiation from surface metal − semiconductor grating structures

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Enhancement of terahertz radiation from coherent optical phonons via impulsive interference of excitons in GaAs/AlAs multiple quantum wells

Cited by 4 publications

References 11 publications

Longitudinal optical (LO) and LO-like phonon resonant mid-infrared radiation emission and absorption by surface micro-structures on III-nitrides

Longitudinal optical (LO) and LO-like phonon resonant mid-infrared radiation emission and absorption by surface micro-structures on III-nitrides

Mid-infrared thermal radiation resonating with longitudinal-optical like phonon from n++-doped GaN–semi-insulating GaN grating structure

Impact of material-dependent radiation – longitudinal optical phonon interaction on thermal electric-dipole radiation from surface metal − semiconductor grating structures

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Product

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Mid-infrared thermal radiation resonating with longitudinal-optical like phonon from n⁺⁺-doped GaN–semi-insulating GaN grating structure